Treating textile materials and articles made therefrom



Patented July 12, 1938 1 UNITED STATES TREATING TEXTILE MATERIALS ANDARTI- CLES MADE THEREFROM James Craik, Stevenston, Ayrshire, Scotland,as-,

signor to Imperial Chemical Industries a corporation of Great BritainNo-Drawing. Original application September 18,

1935, Serial No. 41,175. Divided and this application June '7, 1937,Serial No. 146,966.

Great Britain October 12, 1934 12 Claims.

This is a divisional application and relates to the subject-matter whichhas been divided out from my copending application for patent SerialNumber 41,175, filed September 18, 1935.

5 This invention relates to methods of treating textile materials toimprove their appearance and more particularly to methods of treatinglustrous textile materials such as yarns, and woven, knitted or othertextiles or articles made therefrom in order to reduce their luster.Although the invention is of primary usefulness in the treatment ofyarns and fabrics made from viscose, or other forms of regeneratedcellulose artificial silk, or

cellulose esters or ethers for instance cellulose acetate artificialsilk, in other words rayon in general, it also can be used to advantagefor reducing the luster of natural silk and mercerized materials.

For some years after the introduction of syn- 10 thetic textiles thehigh luster of these materials was considered a desirable feature, but achange in taste caused the brilliantly lustrous yarns to lose favor formost purposes, and now there is a decided preference for yarns andfabrics of dull appearance.

This invention therefore, has as an object the provision of methods ofimproving the appearance of textiles in accord with present day taste. Afurther object is to provide treatments for textiles which will givethem a dull finish highly resistant to removal by laundering. Otherobjects and advantages of the invention will be pointed out in thefollowing description or will be apparent from such description. Theseobjects 5 are accomplished by my invention wherein various dullingagents are applied to textile mate- L pletely soluble in aqueous causticalkali solution under ordinary conditions, but soluble therein at lowtemperature, and wherein the impregnated textiles are subsequentlytreated with an acid to I desolubilize the coating medium. By thedefinition, cellulose derivative of the kind incompletely soluble inaqueous caustic alkali solution under ordinary conditions, is meant agroup of low-substituted cellulose derivatives comprising hydroxyalkylcellulose (glycol ether of cellulose) methyl and ethyl ethers ofcellulose and certain inorganic esters of cellulose, e. g. the sulfatescontaining a low percentage of the, ester group. To further clarify themeaning of low-substituted as used herein it may be explained that alow-substituted cellulose derivative is one in which comparatively fewof the replaceable .hy-

droxyl hydro'gens of the cellulose molecule are replaced or substitutedby etherifying or esterifying radicals. The adjective low does not referto the molecular weight of the radicals entering the cellulose moleculeas substituents, nor to any of their other characteristics, but merelyto the proportion of these radicals introduced.

At the present state of development in the art, applicant is unaware ofa better way to describe the particular cellulosic compounds in which heis interested than by the definition flow-substituted, (that is, withcomparatively few etherifying or esterifying radicals introduced), andby pointing out the striking solubility characteristic. This method, itis thought, .sharply defines the compounds under consideration to thoseexperienced in the art.

It is known that these cellulose bodies when specially prepared underconditions to assure low substitution in the cellulose unit have theproperty of being substantially insoluble in water or aqueous causticalkali at ordinary temperatures, but are capable of being brought intosolution in a dilute aqueous solution of a caustic alkali by chilling(in some cases for a predetermined time) below 0 C. until crystals ofice appear, or else by cooling to a lesser stage (+1 to +3 C.) and usinga colloid mill or dispersing agentsor soluble colloids to aid solution,as described in my British Patent 410,152. Once dissolved, the,temperature of the alkaline solution of cellulose ether or ester can beraised to ordinary or room temperature without causing precipitation orany other bad eflect.

In the preferred form of this invention it is. desirable that theconcentration of caustic alkali should not substantiallyexceed 5% andthe percentage of cellulose derivative dissolved therein should be verylow, for example, in the neighborhood of2 parts per hundred. Theproportion of dulling agent to cellulose derivatives may be variedwidely.

As dulling agents, there EiiIeiE'y'EEnu merous suitable materials suchas zinc oxide, titanium oxide, stannic oxide, tin phosphate, china clay,barium sulphate, antimony oxide and compatible mixtures of these.Materials of this nature may be applied either in suspension as such inthe alkaline cellulose derivative solution,

cipitated by suitable means upon the textile matee rial or articleduring the operation of fixing the cellulosic medium.

In the operation of the process of this invention the textile materialor article made therefrom is passed through a dilute aqueous causticsoda bath containing the dulling agent and cellulose derivative andafter thorough wetting it is passed through pressure rolls to remove theexcess liquid. Alternatively, the solution may be applied to one sideonly of the fabric, in which case it may be advisable not to pass thetreated fabric through nip rolls if there is danger of forcing theliquidthrough the fabric.

The fabric is next treated with an agent to neutralize alkalinity and inthat way fix the pigmented cellulosic coating on the textile fibers.This may be accomplished by means of a bath of dilute aqueous acid, forexample, sulfuric, phosphoric, hydrochloric, formic or acetic acid. Or,if preferable because of the properties of the dulling agent used, theremay be substituted an atmosphere of a mildly acid gas such as carbondioxide. Thus in the case of titanium oxide, stannic oxide, china clayor barium sulphate either a bath of dilute aqueous acid or an atmosphereof carbon dioxide may be used, whereas in the case of zinc oxide whichis more easily soluble in an acid bath, the treatment with carbondioxide is to be preferred. In this case the zinc oxide will be partly.or wholly converted into carbonate.

When the dulling material is applied in the form of an alkalinesolution, the acid chosen for fixing the cellulose derivative must besuch as to produce an insoluble precipitate of pigment; for example,when sodium stannate is employed, dilute phosphoric acid may properly beused as precipitating agent.

The acid treated material is passed into a faintly alkaline washing bathand then is washed with water until the wash Waters are neutral.

The material is next dried and further finished in known manner.

If desired, the alkaline suspension or solution containing the dissolvedcellulose derivatives and the dulling agent may also contain wettingagents such as sulfonic acids of high molecular weight or softeningmaterials such as the product sold under the registered trade mark.Cirrasol S A (a mixture of cetyl alcohol and cetyl sodium sulfonate)This invention is illustrated but not limited by the following examples,in which the parts are by weight.

Example 1 A glycol cellulose ether of the kind incompletely soluble incaustic soda of any concentration but capable of solution on chilling in5% sodium hydroxide solution until crystals of ice appear is broughtinto solution in sodium hydroxide, by mixing 2 parts of the glycolcellulose with 100 parts of 4.5% sodium hydroxide solution in thepresence of 1% calculated on weight of glycol cellulose, of thedispersing agent sold umder the registered trade mark Perrninal (anisopropylated naphthalene sulfonate) according to the method describedin British Patent No. 410,152. 6 parts of finely ground zinc oxide arethen introduced into the solution, and the whole is stirred. 2 parts ofthe paste sold under the registered trade mark Cirrasol S A" extendedwith 12 parts of water is then added to the bath. A length of wovenviscose fabric is then passed rapidly through the bath so the period ofcontact is about 2 seconds, and subsequently passes through the niprolls to rubber covered rollers and thereafter into a chamber containingan excess of carbon dioxide until the glycol cellulose has beencoagulated. The cloth is then washed, dried, and broken.

Example 2 A length of knitted cellulose acetate fabric is passed into ahath made up as in Example 1, containing titanium dioxide instead ofzinc oxide. After passing through the nip rolls, the fabric is passedrapidly through a bath containing 3% sulphuric acid, after which it ispassed through a neutralizing bath of very dilute ammonia, and is thenwashed with water, and dried.

Where desired, the de-lustcred textiles or articles made therefrom canbe dyed with suitable dyes, and it will be understood that when thematerial is to be dyed it is usually necessary that the dulling agentshould be white.

Lustrous textile materials are effectively delustered by thecomparatively simple, inexpensive non-hazardous procedure of thisinvention, and the dull appearance is remarkably permanent even when thetreated materials are submitted to frequent laundering.

As many apparently widely different embodiments of this invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that I do not limit myself to the specific embodimentsthereof except as defined in the appended claims.

I claim:

1. In a delustring process, the steps which comprise impregnatinglustrous textile materials and articles made therefrom with apigmentcarrying dilute aqueous caustic alkali solution of alow-substituted cellulose derivative of incomplete solubility in dilutecaustic alkali solution at room temperature but completely solubletherein at temperatures below 10 0., and thereafter neutralizingalkalinity of the treated article with acid.

2. A process according to claim 1 in which the pigment used is zincoxide.

3. A process according to claim 1 in which the pigment used is titaniumdioxide.

4. A process according to claim 1 in which the pigment used is bariumsulfate.

5. In a delustring process, the steps which I comprise impregnatinglustrous textile materials and articles made therefrom with an aqueoussolution containing a dulling pigment, and by weight less than 10% ofcaustic alkali and less than 5% of a low-substituted cellulosederivative of incomplete solubility in dilute caustic alkali solution atroom temperature but completely soluble therein at temperatures below 10C., and thereafter neutralizing alkalinity of the treated article withacid.

6. In a delustring process, the steps which comprise impregnatinglustrous artificial and natural silks and articles made therefrom with apigmented dilute aqueous caustic alkali solution of a low-substitutedcellulose ether of incomplete solubility in dilute caustic alkalisolution at room temperature but completely soluble therein attemperatures below 10 C., and thereafter neutralizing alkalinity of thetreated article with acid.

'7. A process as claimed in claim 6 in which the impregnating solutionalso contains wetting and dispersing agents.

8. A process according to claim 6 in which the impregnating solutionalso contains a mixture of cetyl alcohol and cetyl sodium sulfonate.

\ of incomplete solubility in dilute caustic alkali solution at roomtemperature but completely soluble therein at temperatures below 10 0.,and thereafter neutralizing alkalinity of the treated article with acid.

10. A process according to claim 9 in which the alkyl cellulose ismethyl cellulose.

11. A process according/to claim 9 in which the alkyl cellulose is ethylcellulose.

12. In a delustrin'g process, the steps which comprise impregnatinglustrous artificial and natural silks and articles made therefrom with apigment-carrying dilute aqueous caustic alkali solution of alow-substituted glycol ether of cellulose of incomplete solubilityindilute caustic alkali solution at room temperature but completelysoluble therein at temperatures below 10 C., and thereafter neutralizingalkalinity of the treated article with acid.

1 JAMES ORAIK.

